Conventional time domain multiple access (TDMA) satellite communication networks employ multiple radio stations which communicate through an earth satellite repeater by transmitting time-synchronized bursts of radio energy relative to the repeater and which receive a time multiplex composite of bursts containing corresponding modulated information from the repeater. In TDMA operations, multiple ground stations associated with radio signaling nodes transmit bursts of timeconcentrated information signals on a shared carrier frequency spectrum and receive the same information signals after repetition by the satellite repeater on a shifted carrier frequency spectrum. Each ground station is assigned a particular time slot in a continuum of recurrent frames for transmission of its bursts and for the reception of its own bursts and the bursts of other stations. The bursts interleave at the satellite in close time formation without overlapping. Each earth station includes connections to incoming digital lines originating from terrestrial sources. These input lines are respectively connected to digital data ports on a satellite communications controller (SCC) at the station.
In a modern satellite communications controller, the overall control operation is carried out by a local host processor which must initiate and supervise digital switching operations, storage transfer operations, operating system program instructions, peripheral equipment coordination operations, and call processing operations. This wide variety of functions places great demands upon the local host processor and oftentimes some of the peripheral demands placed upon the host processor cannot be satisfied because the host processor cannot attend to those tasks while enaging in higher priority operations initiating and supervising other functions in the satellite communications controller.
Typical prior art techniques for coordinating the operation of a plurality of diverse subunits is typified by one example of the prior art which describes a computer apparatus for determining the transmission and coding configuration which characterize dissimilar remote terminals in a time shared computer system. Electrical communication is established between an individual remote terminal and a line adapter unit, a single standard character is then transmitted from the remote terminal to the line adapter unit. The standard character is analyzed to determine which one of a variety of transmission rates and code configurations characterize the particular terminal. In response to the analysis of the standard character, data communication is established between the remote terminal and the computer at the indicated transmission rate in the indicated code. An approach such as this places a substantial computing load on the host processor and is not suitable for quick response control of a plurality of asynchronous subsystems having different data rates, without an investment in large quantities of hardware to execute control operations.